Clinical Studies: a) The clinical phenotype in patients with and female carriers of the oculocerebrorenal syndrome of Lowe (OCRL) has been more precisely defined. Patients present a variety of specific ocular, renal, bone, central nervous system, muscle, and soft tissue complications. Heterozygote complications are predominantly limited to the ocular lens, but some degree of renal and central nervous system complications may be present. b) Neurologic manifestations of nephropathic cystinosis, hereditary hemorrhagic telangiectasia, and von Hippel-Lindau disease, genetic diseases that do not present with neurologic complications, have been described. c) The lack of specificity for brain anatomic lesions leading to self injurious behavior in retarded children has been demonstrated. Laboratory Studies: a) Elevation of nucleotide pyrophosphatase levels in OCRL cells is not a specific cellular phenotype for OCRL and is unlikely to be useful in attempts at isolating the gene for OCRL. b) In an amphibian system, we have isolated and sequenced full length cDNA clones for XNIF, a neuronal intermediate filament with unusual amino acid sequence, genomic organization, developmental expression profile, and adult neuron specificity, and isolated multiple clones for Xenopus low molecular weight neurofilament protein, (XNF-L).